Datasheet

Instruction/Operation Instruction Format
Byte 1 Byte 2 Byte 3 Byte 4
Write Fuse High bits 0xAC 0xA8 0x00 data byte in
Write Extended Fuse Bits 0xAC 0xA4 0x00 data byte in
Note:
1. Not all instructions are applicable for all parts.
2. a = address.
3. Bits are programmed ‘0’, unprogrammed ‘1’.
4. To ensure future compatibility, unused Fuses and Lock bits should be unprogrammed (‘1’) .
5. Refer to the corresponding section for Fuse and Lock bits, Calibration and Signature bytes and
Page size.
6. Instructions accessing program memory use a word address. This address may be random within
the page range.
7. See http://www.atmel.com/avr for Application Notes regarding programming and programmers.
8. WORDS.
If the LSB in RDY/BSY data byte out is ‘1’, a programming operation is still pending. Wait until this bit
returns ‘0’ before the next instruction is carried out.
Within the same page, the low data byte must be loaded prior to the high data byte.
After data is loaded to the page buffer, program the EEPROM page, Please refer to the following figure.
Figure 28-7. Serial Programming Instruction example
Byte 1 Byte 2 Byte 3 Byte 4
Adr MSB
Adr LSB
Bit 15 B 0
Serial Programming Instruction
Program Memory/
EEPROM Memory
Page 0
Page 1
Page 2
Page N-1
Page Buffer
Write Program Memory Page/
Write EEPROM Memory Page
Load Program Memory Page (High/Low Byte)/
Load EEPROM Memory Page (page access)
Byte 1 Byte 2 Byte 3 Byte 4
Bit 15 B 0
Adr MSB Adr LSB
Page Offset
Page Number
Atmel ATmega644A [DATASHEET]
Atmel-42716C-ATmega644A_Datasheet_Complete-10/2016
380